if you're referring to the ask to mail stuff in after inputting 1099-B at summary level but it has adjustments for wash sales or AMD etc; then inputting specific sales from 1099-B as "one by one" instead of sales summaries should generate 8949 for those entries and remove the need to mail things in. you can enter as a mix, just put the lots/sales with adjustments as one-by-one; and calculate the balance remaining of the 1099-B to input as a summary.
(experience based on desktop version but presumably online is similar)
